The Strategic Defense Initiative Organization plan to conduct Demonstration/Validation tests of the SSTS technology. These tests will demonstrate the ability of the technology to perform required tasks, and will validate a future decision on whether to proceed with Full-Scale Development. Demonstration/Validation tests would be conducted at the Arnold Engineering Development Center, Nevada Test Site, Vandenberg Air Force Base/Western Test Range, Cape Canaveral Air Force Station/Eastern Test Range, Kennedy Space Center, National Test Facility, and at contractor facilities. Tests would include analyses, simulations, component/assembly tests, and flight tests. This document addresses the potential environmental consequences of the Demonstration/Validation testing of the SSTS technology. (jhd)